These Ammonites (Harpoceras (big) and Dactyloceras (small) Harpoceras was found in the lower jurassic layers (Lias epsilon, Posidonienschiefer) of Holzmaden in Germany.
The bug Animal measures about 23 cm in diameter. It is located in unbroken original slab which measures about 46 cm x 41 cm.
The stone also contains some more smaller sized Ammonites (Dactyloceras).
No manipulations at all.